Automatic circuit breaker



June 30, 1931. J. SACHS AUTOMATIC CIRCUIT BREAKER '2 Sheets-Sheet l Original Filed Jan. 16, 1929 .llllll June 30, 1931. J. SACHS AUTOMATIC CIRCUIT BREAKER 2 sheets-'sheet 2 Original Filed Jan. 16. 1929 Patented June 30, 1931 UNITED STATES PATENT OFFICE AUTOMATIC CIRCUIT BREAKER` Application l'ed January 16, 1929, Serial No. 332,925. Renewed February 26, 1931.

The invention relates particularly to an automatic circuit breaker of the type disclosed in my copending applications for Automatic circuit breakers, Serial No. 271,819

'5 filed 'April 21, 1928, Serial No. 283,060 iiled June 5th, 1928, and Serial No. 332,924 filed on even date herewith.

One of the objects of the invention is to provide a circuit breaker of the type disclosed in the said applications having a rectilinearly movable handle for operating; a pivotally movable actuator and contact member. In accordance with the invention various improved details are provided whereby the before stated general object is eifectively attained.

As disclosed in the third said application the automatic circuit breakin action takes place entirely independently o the operating handle and the said handle is nevertheless automatically moved to its open-circuit position whenever the circuit breaker is auto* matically operated to break the circuit. Thus after an automatic breaking of the circuit it is only necessary to move the handle in the regular way from its open-circuit posi.- tion to its closed-circuit position in order to re-establish the circuit. One of the objects of the present invention is to provide such a circuitbreaker wherein the means for actuating the movable contact member is pivotally I movable and wherein the handle is movable rectilinearly.

A further object of the invention is to provide certain improved details of construction and mounting for the electric contacts, par ticularly the stationary contacts.

Other objects of the invention will be apparent from the following specification and claims.

In the accompanying drawings ,If have shown one embodiment of the invention similar in some respects to the disclosure in the said copending application, but it will be understood that the drawings are intended for illustrative purposes only and are not'to` be construed as definin or limiting the scope of the invention,I the c aims forming a part of this specification being relied upon for that purpose. 4 v

Of the drawings: Fig. 1 is a front view ofa circuit breakerv embodying the invention, theenclosing cover y Fig. 3 is a vertical sectional view taken along the line 3 3 of Fig. 2.

Fig. 4 is a transverse sectional' view taken along the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary perspective view showlng the stationary and movable,con tacts and associated parts.

Figs. 6 and 7 are detail perspective views of the carbon contacts.

' Fig. 8 is an enlarged fragmentary transvrlse secgional view taken along the hne 8-8 o 1g.

Figs. 9 and 10 are side views similar to Fig. 2 but showing'the parts in different relat1ve positions, the base and casing being omitted.

Referring to the drawings, it will be observed that the main body of the circuit breaker unit comprises two spaced side plates 1b, 1b and metallic cross members 2" and 3b threaded at their ends and connected with the side plates by means of nuts 4b, 4". The said body of the circuit breaker unit is connected With a base 5Ib by means of screws 6", 6l extending through the members 2b and 3b and engaging metal plates 7 b and 8" carried by the base. The said plates Pand 8" are provided respectively with wire terminals 50b and 51.

I provide a contact member which is movablly)I mounted with respect to the body, prefera ly being mounted for pivotal movement. As illustrated the contact member includes two side plates 9b, 9b which are pivotally mounted upon a transverse rod 10b supported at its ends by means of the side plates 1b, 1b ofthe body, the ends of the rod being reduced in diameter and extending through holes in the plates. .The side plates 95, 9b are spaced from the. side plates 1"-, 1b by means of washers 11", -11jand 'are spaced fromeach other by means of bushings 12", 12b surrounding the rod 10". '.The contact member is biased to its open-circuit position by means tionary contacts. The stationarya'nd mov-f able contacts differ considerably from those disclosed in my said copending application, the contacts being arranged with theirmain contact faces perpendicular to the pivotal axis of the contactmember instead of parallel therewith as `heretofore shownand described. The main stationary contact 13" at the right hand side is formed as a part of almetalllc strip 13 which extends along the outer surface of the corresponding plate 1". Asshown in detail in Figs. 5, 8 and 9 the strip 13 is/.held in place by means of the nut 4" at the right hand end of the `cross' member 2". The said strip 13' is preferably longitudinally slotted as shown and the upper endsof the several sections of the strip are bent inward topextend through an oper-ing in` the side plate so as to-provide contact faces adjacent the inner face ofthe said side plate. The le'ft hand main stationary-contact coinprises a similar strip 13 and is similarly held b means of the nut 4" at the left hand end o the cross member 2". The said left hand contact stri 13 is held in place by means of a flange bushing 69 of conducting materialvso that the said contact strip 13 is electricall connected with the cross member 2" and t us with the terminal 50".A The right hand contact strip 13 'is held inplace by means of a flanged bushing 70 of insulating material interposed between, it and the nut 4". Thus the said contact strip 13 v is insulated from the cross member 2". The' said strip 13 is electrically connected with the cross member 3" at the opposite end by means of a conducting strap 71 which ex.

tends ,along the side of the side plate. Preferably a washer 72 of conducting material is provided to s ace the conducting strap 71 outward away rom the contactmember. The

5^, strap 71 is provided with an opening at one end through which the bushing 70 extends and with an openingat the other end for receiving the extended threaded portion of the cross member 3". Thus the right hand contact 13"'is electrically connected with the upper cross member 3" and withV the wire terminal 51", i y

" TheF main movable contacts 16",16" are connected with a transverse insulating member. 17" bymeansof screws 18", 18". Engaging each contact 16" and located'between it and the insulating member 17" is a con-l `ductor y73, as shownqin Figs. 5,' 9 and 10, which serves as al means for the attachment of the correspondingend of a, U-shaped bimetallicstrip 21". Screws 74, 74 are provided for holding the strip in place. Each lof the said contacts 16" extends outward through a hole in the corresponding side plate 9" to yprovide an outer contact surface as shown, the end o'f the contact strip being carried backward through the hole and then along the inner surface of the side plate where it is held by means of a rivet 75. The contact faces of the contacts 16", 16" are ada ted to engage respectively with the contact aces of the contacts 13", 13" as shown in Fig. 3.

Afl actuator 20" is mounted upon the transverse-rod 10" between the two bushings 12", 12" thereon. The bi-metallic strip 21" normally engages the actuator 20" and serves in and of itself as a normally operative mechanical connection between the actuator and the contact member. When the thermal strip is normally operative as a mechanical connection the actuator may c ontrol the movements of the contact member to its closed-circuit or its open-circuit positions for ordinary switching purposes. However, .upon the attainment of a normal current conditions the thermal strip is deiected outward so as to disengage the actuator and permit the contact member to move to its open-v circuit position under the action of the springs 19", 19". l

. In addition to the main contacts A13" and 16" I have shown auxiliary carbon contacts. Associated with each of the main stationary contacts 13" is an auxiliary carbon contact shown in detail in Fig. 6. The contact 35" is held in place by a resilient strip 34" which extends along the outer surface ofthe corresponding Acontact strip 13 and isheld by the corresponding nut 4". Adjacent each of the main movable contacts 16" is a carbon contact 37" shown indetail in Fig. 7, this being held in place by means of the corresponding screw 18". The construction is such that when the contact member is moved from its closedcircuit position to its open-circuit position the two carbon contacts engage each otheras the main contacts disenga each other and the carbon contacts remain in engagement for an instant so that any arcing that may occur takes place between the carbon contacts rather than between the main contacts.

VCarried by the side plates 1", 1" are two transverse pms 76, 76 held in place by means of nuts 77, 77. These transverse pins serve to assist in the proper spacing of the side plates,

and the lower pin 76 serves .as a means fory guiding a vertically movable slide 78. This slide has avertical-slot through which the said pins7 6, 76 extend, and as a matterV of f convenience the slide preferably comprises two arts 79 and 8 The front part 79 may be'o insulating mate al. The said slide 78 lll carries an operating member or handle 31", the handle being provided with a rearward extending screw 81 which extends through a hole inthe front member 79 and which is threaded into the central portion of the rear member 80. Thus the handle serves to hold the two portions of the slide in engagement with each other. The weight of the slide and of the handle is such that the said parts tend to move to their lower positions as shown in' 21 to the actuator 2()b and is thereby trans-- mitted to the link 24b which presses directly forward substantially per endicularly to the .direction of movement o t-he slide 78. The

parts may be arranged withthe pivotal axis at 29b at the same level with or above the axis 27" as may be found necessary. The result of the construction is that so long as pressure is applied to the actuator by means of the bi-metallic stri the link .2lib serves to hold the slide 78 and t e handle 31h in their upper positions as shown in Fig. 2 thus overcoming the tendency of the said slide andhandle to move downward by gravity. Thus the slide 78 and the link 24'b act as a restraining means to normally prevent the movement of the handle and actuator to o en-circuit positions.

Thehandle 31b may moved downward or upward as desired and when so moved it serves to move the contact member andthe movable contacts thereon for ordinary switching purposes. Fig. 2 shows the arts in closed-circuit positions and Fig. 9 s ows the handle moved downward and the contact member swung upward so as to break the circuit.

Upon the. attainment of abnormal current conditions, as for instance the assage of excess current, the bi-metallic strip 2lb is automatically disengaged from the actuator 20? thus rendering inoperative the mechanical connection between the actuator and the contact member. The .contact member then automatically moves to its open-circuit position under the iniuence of the springs 19h, 19h. It will be understood that this automatic movement takes place independently of the actuator so that the holding of the handle and they actuator in closed-circuit position as shown* in Fig. 10 will not interfere with the automatic opening. If the handle is not held in the closed-circuit position the handle and the actuator will immediately move to their 35 lower open-circuit positions as soon as the tion, electro-responsivel pressure on the actuator is released by reason of the disen agement of the thermal strip therefrom. bviously the release of the pressure on the actuator 20b releases the pressure on the link 24h thus permitting the slide and handle to move downward by gravity. Thus as the Contact member moves toward its open-circuit position, thehandle and the actuator move substantially simultaneously toward their open-circuit positions. The contact member will reach its open-circuit position first but the actuator and handle follow closely thereafter, the mechanical connection between the actuator and the contact member being substantially immediately restored by reasonof the rc-engagement of the thermal strip 21b with the actuator 20h. When the circuit is broken as the result of an ordinary overload the thermal strip is deflected only far enough to effect release and it very quickly cools sufficiently to eii'ect re-engagement; but when the circuit is broken as the result of a short circuit the heating of the strip may be such as to deflect it more than enough to effect release and in such a case an appreciable interval of time may elapse before the strip cools suiiiciently to effect re-engagement.

As shown the circuit breaker is enclosed in a casing 59b which is held in engagement wi h the base 5" by means of screws 66", 66". The casing 59b has an opening 67b in the front thereof through which the handle 31b projects, the said opening being long enough to permit the Vertical movement 1 of the handle. It will be understood that the front member-79 of the slide prevents access through the said opening 67b to the interior of the casin What I c aim is:

1. In an automatic circuit breaker, the combination of a stationary support, an actuator pivotally mounted on the support, a contact member also ivotally mounted on the support and biased) for movement independently 0f the actuator to its open circuit posicontrolled means serving to effect operatlve mechanical connection between the actuator and the contact member and actin to lrelease said mechanical .connection umier abnormal current'conditions to permit the contact member to au-' tomatically move independently of the actuator to its said open circuit position, a manually operable slide carried b the stationary support and guided for rectilmear movement, and means connecting the slide with the actuator whereby movement of the slide to on or ofi' position normally effects corresponding pivotal movement of the actuator and the the-'said slide and the said actuator respectively.

3. In an automatic circuit breaker, the combination of a main body comprising two spaced substantially parallel side plates, an actuator pivotally mounted between the plates for movement about a transverse axis, a contact member movably mounted between the plates and biased for movement independently of the actuator to its open-circuit position, an electro-responsively` controlled mechanical connection between the actuator and the contact member which connection is normally operative and is automatically rendered inoperative upon the passage of excess current to permit the contact member to automatically move independently of the actuator to its open-circuit position, l-a manually operable slide carried by the plates and guided for rectilinear` movement in a direction parallel therewith, and a means .connecting the slide with the actuator and enabling the slide to move both the actuator and' the Contact member for ordinary switching purposes. v

4. A circuit breaker as set forth in claim 3 wherein the means connecting the slide with the actuator is a link pivotally connected therewith for relative movement about axes parallel with the pivotal axis of the actuator.

5. Acircuit breaker as set forth in claim 3 wherein the slide extends transversely between the side plates near the front thereof and is guided at its edges by the said plates.

6. A circuit breaker as set forth in claim 3 whereinl there are transverse pins between the side plates and wherein the slide has a slot through which the pins extend, the length of the slot permitting the required rectilinear movement of the slide and the pins serving as guides for such movement. l

7. In an automatic circuit breaker, the combination of a main body comprising two spaced substantially parallel side plates, an actuator pivotally mounted between the 'plates for movement about a transverse axis,

a contactmember movably mounted between the plates and biased for movement independently of the actuator to its open-circuit l position, anelectro-responsively controlled mechanical connection between the actuator and the contact member which connection is normally operative and is automatically rendered inoperative upon the passage of excess y current to permit the contact member to automatically move independently of the actuator to its .open-circuit position, two transverse pins extending between the side plates near the front thereof, a two-partslidehaving one part behind the pins "and the other part in front thereof so that the pins serve to guide the slide for rectilinear movement, a handle connected with the slide, and a meansconnecty ingthe slide with the actuator and enabling the slitleto move both the actuator and the contact member for ordinary switching puroses. P 8. A. circuit breaker as set forth in claim 7 wherein the handle is located at the front of the slide and serves to prevent separation of the two parts thereof. l l

9. An automatic circuit breaker comprising in combination, a movable contact member biased toward its open-circuit position, a. manually operable pivotally mounted'actuator biased toward its open-circuit position and normally mechanically connected with the contact member so as to be ca able of operating it, rectilinearly movab e slide relatively movably connected with the actuator to operate it and thecontact member for ordinary switching purposes, a restraining means .adapted to prevent automatic movement of the actuatorand slide from their closed-circuit positions to their open-circuit positions, the said restraining means being rendered effective by therelative movement between the slide and actuator as the former moves the latter to its closed-circuit position, and an electro-responsive means serving upon the passage of excess current to release l pivotally movable actuator, an electro-responsively controlled mechanical connection between the actuator and the contact member which connection is normally operative and is automatically rendered inoperative upon the passage of eXcess-crrentfto permit the contact member to automatically move independently of the actuator to its open-circuit osition, a rectilinearly movable slide iased toward its o en-circuit position, and means associated with the slide and the actuator and normally enabling the slideto operate bothy the actuator and thecontact member for ordinary switchingjpurposes, .the last saidv means vservingwhen `the slide and actuator are in closed-circuit positions to prevent automatic movement thereof to open-circuit positions so long as 'the actuatv or 1s biased to open-circuit position ,by

reason of the mechanical connection between it and the contact member' and the said means upon the inoperativeness` of the said mechanical connection releasing'the slide and actuator .f1-to4 permit automatic movement thereof pen-circuit positions substantially simultaneously with the movement of the contact member to open-circuit position.

11. A circuit breaker asset forth in claim 10 wherein the contact member and actuator are pivoted for movementabout a common axis and are maintained in fixed relationship to each other during normal switching movements.

12. An automatic circuit breaker comprising in combination, a movable Contact member biased toward its open-circuit position, a

pivotally movable actuator, an electro-re sponsively controlled mechanical connection between the actuator and the contact member which connection is normally operative land is automatically rendered inoperative upon the passage of excess current to permit the contact member to automatically move independently of the actuator to its open-circuit position, a slide movable in a direction per pendicular to the pivotal axis of the actuator and biased toward its open-circuit position, and a link pivoted at its ends to the slide and the actuator respectively and normally enabling the slide to operate both the actuator and the contact member for ordinary switching purposes, the said link being substantially perpendicular to the direction of movement of the slide when the slide and actuator arev in closed-circuit positions thereby preventing automatic movement thereof to open-circuit positions so long as the actuator is biased to open-circuit position by reason of the mechanical connection between it and-the contact member and the said link upon the inoperativeness of the said mechanical connection releasing the slide and actuator to permit automatic movement thereof to open-circuit positions substantially simultaneously with the movement of the contact member to opencircuit position.`

13. An automatic circuit breaker comprising in combination, a rectilinearlyv movable operating member, a pivotally movable actuator, a pivotally movable contact member biased independently of they actuator toward its open-circuit posltion and releasably connectible with the actuatorso as to be normally controlled therebyfformovement to itsl closed-circuit or its opencircuit position, an electro-responsive means bodily movable as an entirety.when the actuator and contact member are moved', the said electro-responsive means serving u on the attainment of abnormal current con itions to cause the release of the contact memberfrom the actuator for independent automatic circuit-opening movement, 'and a means enabling the rectilinearly movable operating member to effect the movement of the pivotally movable actuator and also normally serving to prevent automatic movement of the operating member and Aactuator from their closed-circuit osition, the said means being rendered e ective' to prevent such automatic movement as the result of stress transmitted from the contact member to the actuator through the said mechanical connection and -becomin ineffective for such purpose 4upon the diminution or absence of the aforesaid transmitted stress.

14. An automatic circuit breaker as set forth in claim 13, wherein the means enabling the operating member to effect the movement of the actuator is a pivoted link and wherein the electro-responsive means is an electrothermal strip serving in and ofitself as the mechanical connection between the actuator and the contact member and adapted to become 'inoperative as such connection upon the passage of excess current.

15. In an automatic circuit breaker, the combination of 'a main body comprising two spaced substantially parallel side plates, two conductin cross members connecting the plates adgacent opposite ends thereof, a manually operable actuator pivotally mounted between the plates for movement about a transverse axis, a contact member pivotally mounted between the plates for movement about the same transverse axis independently of the actuator, the said contact member being biased toward its open-circuit position, two movable contacts electrically connected with each other and carried b the contact member at opposite sides thereo ,electro-responsively controlled means including a mechanical connection between the actuator and the contact member which connection is normally operative and is automatically releasable upon the passage of excess current to permit the contact member to automatically move independently of the actuator to its open-circuit position, two similar stationary contacts carried respectively by the side plates in position to be respectively engaged and disengaged by the movable contacts on the contact member and each comprising a resilient strip connected with the corresponding side plate adjacent one of the cross members, the two 'strips both extending in the same direction longitudinally of the side plates, means electricall connecting one strip directly with the immediately adjacent cross member, and a conductor extending longitudinally of the corresponding side plate for electrically connecting the other strip with the cross member at the opposite end.

16. A circuit breaker as set forth in claim 15 wherein at least one of the cross members 

